feat(settings): split Chat & Contacts into Appearance | Messaging columns

Break up the tall, left-heavy Chat & Contacts card internally: Appearance on
the left, Messaging on the right when the card is wide (fills the width, ~halves
the height). Same Indent technique as the Node & Security card; the row helpers
retarget their leftX/rowW per column so controls right-align within each. The
narrow chat-settings modal stays single-column.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/ui/windows/chat_tab.cpp

@@ -1859,8 +1859,10 @@ void RenderChatSettingsControls(App* app, float contentWidth)
     // Right-align controls to the row's true right edge. The Settings tab renders us inside a GlassCard
     // whose content region isn't narrowed to the card padding, so it passes an explicit contentWidth;
     // the chat modal's dialog content region is correct, so it passes 0 (auto).
-    const float leftX = ImGui::GetCursorPosX();
+    // leftX/rowW define the current column the rows lay out in; retargeted below
-    const float rowW  = (contentWidth > 0.0f) ? contentWidth : ImGui::GetContentRegionAvail().x;
+    // to split Appearance | Messaging into two columns when the card is wide.
+    float leftX = ImGui::GetCursorPosX();
+    float rowW  = (contentWidth > 0.0f) ? contentWidth : ImGui::GetContentRegionAvail().x;
 
     // Label left, control right-aligned within [leftX, leftX+rowW]. Leaves the cursor at the control origin.
     auto beginRow = [&](const char* label) {
@@ -1925,6 +1927,17 @@ void RenderChatSettingsControls(App* app, float contentWidth)
         return result;
     };
 
+    // Two internal columns when the card is wide enough: Appearance on the left,
+    // Messaging on the right — fills the width and roughly halves the height.
+    // (Mirrors the Node & Security card.) Narrow (the chat modal) stays single-column.
+    const float chatColGap = 24.0f * dp;
+    const bool  chatTwoCol = rowW > 760.0f * dp;
+    const float chatColW   = chatTwoCol ? (rowW - chatColGap) * 0.5f : rowW;
+    const float chatBaseLeftX = leftX;
+    const float chatTopY = ImGui::GetCursorPosY();
+    float chatLeftBottomY = 0.0f;
+    if (chatTwoCol) rowW = chatColW;   // left column width
+
     // ── Appearance ────────────────────────────────────────────────────────────────
     section("chat_sec_appearance");
     // Emoji style (monochrome / color). Color needs a FreeType build (native + the cross-built Windows
@@ -1965,6 +1978,15 @@ void RenderChatSettingsControls(App* app, float contentWidth)
         }
     }
 
+    // Move Messaging into the right column (float it with Indent so every row's
+    // line-start holds the column; retarget leftX so controls right-align in it).
+    if (chatTwoCol) {
+        chatLeftBottomY = ImGui::GetCursorPosY();
+        ImGui::SetCursorPosY(chatTopY);
+        ImGui::Indent(chatColW + chatColGap);
+        leftX = chatBaseLeftX + chatColW + chatColGap;
+    }
+
     // ── Messaging ─────────────────────────────────────────────────────────────────
     section("chat_sec_messaging");
     // Message poll rate (full-node 0-conf fast-scan cadence) — slider.
@@ -1988,6 +2010,14 @@ void RenderChatSettingsControls(App* app, float contentWidth)
         bool v = st->getChatEnterSends();
         if (ImGui::Checkbox(TR("chat_opt_enter_sends"), &v)) { st->setChatEnterSends(v); st->save(); }
     }
+
+    // Close the two-column band: un-indent and drop below the taller column.
+    if (chatTwoCol) {
+        ImGui::Unindent(chatColW + chatColGap);
+        const float chatRightBottomY = ImGui::GetCursorPosY();
+        ImGui::SetCursorPosX(chatBaseLeftX);
+        ImGui::SetCursorPosY(std::max(chatLeftBottomY, chatRightBottomY));
+    }
 }
 
 } // namespace ui